Flying Capacitor Converter Bypass Control for Faulty Switch Levels
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Solution Overview
Problem
Multi-level flying capacitor converters face challenges in maintaining availability and reliability due to faulty switches, which can lead to system failure if not properly managed.
Innovation Solution
The method involves detecting a faulty switch, discharging all capacitors, closing bypass switches to bypass the faulty level, adapting the modulation of other converter levels, and restarting the converter, thereby allowing the system to continue operating with reduced levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bypass switches are added to each converter level, then the reliability of the converter is improved by enabling fault tolerance, but the device complexity increases due to additional switches and control circuitry
Solution Approach 1:
The converter is divided into multiple independent converter levels, each with its own bypass switches. This segmentation allows individual levels to be isolated and bypassed when faulty, preventing single-point failures from causing complete system failure and thereby improving reliability while maintaining manageable complexity through modular design.
Solution Approach 2:
Bypass switches are pre-installed at each converter level before operation begins. These backup paths are prepared in advance to cushion against potential switch failures, allowing the system to maintain operation even when converter switches fail, thus improving reliability without requiring complex real-time decision-making.
2Object-affected harmful factors
If all capacitors are discharged when a faulty switch is detected, then the safety of the converter is improved by preventing damage propagation, but the productivity decreases due to converter shutdown and restart requirements
Solution Approach 1:
When a faulty switch is detected, the problematic converter level is extracted from the operational system by discharging its capacitor and closing bypass switches. This isolation removes the harmful element from the system, preventing damage propagation to other components while allowing the remaining healthy levels to continue operating.
Solution Approach 2:
Bypass switches act as intermediary elements that can be activated to redirect current flow around faulty converter levels. This mediation allows the system to safely discharge problematic capacitors and isolate failures without completely shutting down the converter, maintaining productivity while ensuring safety.
3Reliability
If the modulation of converter switches is adapted after a fault occurs, then the reliability is improved by enabling continued operation with reduced levels, but the control complexity increases due to dynamic modulation adjustments
Solution Approach 1:
The modulation strategy dynamically adapts based on the operational status of converter levels. When switches are bypassed, the control system adjusts modulation parameters in real-time to accommodate the reduced number of active levels, enabling continued reliable operation while managing control complexity through adaptive rather than static control schemes.
Solution Approach 2:
The control system changes modulation parameters such as switching frequencies and duty cycles based on the number of operational converter levels. This parameter adaptation allows the converter to maintain optimal performance and reliability across different operational configurations, from full capacity to reduced capacity modes.
Data Source
AI summary
A system and method for compensating a faulty switch in a multi-level flying capacitor converter includes a converter capacitor arranged in parallel to an input, a first and second converter switches arranged respectively between first and second ends of the converter capacitor, first and second bypass switches respectively arranged in parallel to the first and second converter switches, wherein operation includes detecting a faulty converter level that includes at least one of the first and second converter switches, discharging all capacitors arranged in parallel to the input of the multi-level converter, wherein all capacitors comprise the converter capacitors and an input capacitor; closing the first and second bypass switches of the faulty converter level; adapting a modulation of the converter switches of the other converter levels; and restarting the multi-level converter.